Field of the Invention
The present invention relates to a solid-state imaging device in which a first substrate and a second substrate are electrically connected by a connection section, and an imaging apparatus.
Description of Related Art
In recent years, in general, video cameras, electronic still cameras, etc. have become widely used. Charge-coupled device (CCD) type or amplification type solid-state imaging devices are used for such cameras. Amplification type solid-state imaging devices guide signal charges generated and stored by photoelectric conversion elements of pixels on which light is incident to amplification units provided at the pixels, and output signals amplified by the amplification units from the pixels. In an amplification type solid-state imaging device, such a plurality of pixels are arranged in a two-dimensional matrix form. Examples of amplification type solid-state imaging devices may include complementary metal oxide semiconductor (CMOS) type solid-state imaging devices, etc. using CMOS transistors.
In the related art, general CMOS type solid-state imaging devices adopt a method of sequentially reading signal charges generated by photoelectric conversion elements of pixels arranged in a two-dimensional matrix form for every row. In such a method, since exposure timings in the photoelectric conversion elements of the pixels are determined depending on starts and ends of reading of signal charges, exposure timings for every row differ. For this reason, when fast-moving subjects are captured using such CMOS type solid-state imaging devices, the subjects are distorted in captured images.
A simultaneous imaging function (a global shutter function) of realizing simultaneousness of storage of signal charges has been suggested to resolve such distortion of subjects. Also, CMOS type solid-state imaging devices having the global shutter function have been used for various purposes. CMOS type solid-state imaging devices having the global shutter function normally need to include storage units with a light-shielding property to store signal charges generated by photoelectric conversion elements until reading thereof is performed. Such conventional CMOS type solid-state imaging devices simultaneously expose all pixels, simultaneously transfer signal charges generated by photoelectric conversion elements from all of the pixels to the storage units, store transferred signal charges once, sequentially convert the signal charges into pixel signals at predetermined reading timings, and read the pixel signals.
However, in conventional CMOS type solid-state imaging devices having the global shutter function, photoelectric conversion elements and storage units should be built on the same plane of the same substrate, and thus an increase of a chip area cannot be avoided. In addition, quality of signals may deteriorate due to noise caused by light and noise caused by leakage currents (dark currents) generated in the storage units during the waiting period until the signal charges stored in the storage units are read.
In order to resolve such problems, a method of preventing an increase of a chip area and reducing noise using a solid-state imaging device in which a first substrate provided with photoelectric conversion elements and a second substrate provided with analog memories (corresponding to storage units) configured to store signal charges generated by the photoelectric conversion elements are adhered is disclosed in Japanese Unexamined Patent Application, First Publication No. 2013-9301. In the solid-state imaging device disclosed in Japanese Unexamined Patent Application, First Publication No. 2013-9301, two substrates are connected to each other by connection sections, and each of the connection sections is shared by two pixels. That is, signal charges generated by two photoelectric conversion elements are transferred to the second substrate from the first substrate via common connection sections, and are stored in two analog memories corresponding to the respective photoelectric conversion elements. Therefore, for example, when each of the connection sections is shared by four pixels, signal charges generated by four photoelectric conversion elements are transferred to the second substrate from the first substrate via common connection sections, and are stored in four analog memories corresponding to the respective photoelectric conversion elements.